The present invention relates to an improved mechatronic device.
Mechatronic devices of the general type under consideration are known. For Example, EP 1 180 602 A1 describes a control-valve device with an electronics box that contains a printed circuit board for mounting electronic components and permits connection to an external bus. One or more solenoid valves can be plugged into the electronics box and thus brought into electrical contact. Electrical control signals arriving from the bus are processed by the electronic unit and distributed to the associated valves. The control-valve device described in EP 1 180 602 A1 does not have any sensors.
DE 100 49 958 A1 describes a fluidic arrangement as well as a valve array and actuator therefor. The associated actuator is provided with a working cylinder with a piston, the position of which can be detected via displacement sensors or limit switches. The output signals of the sensors can be transmitted optionally by hard-wired or wireless means. In the case of wireless communication, the sensors are configured as transponders.
In mechatronic devices, especially in those with solenoid valves, it is frequently necessary to sense one or more pressures and process them in the associated system electronics, which can be contained in a common housing (see e.g., EP 1 152 231 A2). For this purpose, appropriate pressure sensors are built into these devices. Such pressure sensors must be in sealed communication with an associated pressure duct and fixed in such a way that the pressure force can be detected. Furthermore, an electrical connection, usually of the three-wire type, must be established between the pressure sensor and the system electronics.
This conceals certain reliability risks. For example, temperature fluctuations as well as the elasticity of the sensor fixation in combination with pressure fluctuations can cause movements of the pressure sensor relative to the rest of the mechatronic device or system electronics. As a result, the electrical connections can be subjected mechanically to inadmissible stress. Consequently, contacts can be impaired by corrosive friction, bond connections can break due to fatigue and soldered junctions can also suffer fatigue, resulting in intermittent contact.
Furthermore, the interface to the pneumatic or hydraulic pressure duct can become prone to leaks.
Moreover, such electrical connections can hinder or complicate the manufacturing process because, for example, an additional soldering process is required.
Also, a mechatronic device, especially if it is installed in a motor vehicle, is often exposed to electrical interference due to ambient radio waves. This can adversely affect signal transmission.
The application of wireless transmission technology or radio technology for data transmission is known to those skilled in the art from different practical applications using diverse methods.
One such known method involves transponder technology (the use of transponder technology is increasing and, as a result, it can be expected that the cost of the needed modules—transmitter and receiver—will fall). For example, DE 199 24 830 A1 describes a method of utilizing transponder technology to measure the tire pressure of a vehicle tire without contact with the body. A battery to supply power to the sensor located in the tire is not necessary for this purpose. Transmission can take place when a request signal (oscillation) is sent externally, thus exciting a pressure-dependent oscillation circuit in the sensor, which then rapidly returns a corresponding pressure-dependent analog signal.
Another known method involves BLUETOOTH® technology. The article titled “Bluetooth-frequency energy carriers,” Auto & Elektronik January 2002 describes the use of BLUETOOTH™ technology to monitor tire-pressure, wherein both the pressure signals and the energy to supply the pressure sensor are transmitted wirelessly by radio waves.